Title
Zinc oxide spherical-shaped nanostructures: investigation of surface reactivity and interactions with microbial and mammalian cells
Author
Diana Beatrice Visinescu, Mohammed Dyia Hussien, Raluca Negrea, Jose Maria Calderon-Moreno, Simona Schomi, Cristian Dumitru Ene, Ruxandra Barjega, Carmen Mariana Chifiriuc, Marcela Popa, Miruna Stan, Oana Carp
Year
2018
Journal
Langmuir
Abstract
Two ZnO materials of spherical hierarchical morphologies, with hollow (ZnOHS) and solid cores (ZnOSS), were obtained through the hydrolysis of zinc acetylacetonate in 1,4-butanediol. The nature of the defects and surface reactivity for the two ZnO materials were investigated through photoluminescence (PL), X-ray photoelectron (XPS) and electronic paramagnetic resonance (EPR) spectroscopy proving the co-existence of shallow and deep defects and, also, the presence of polyol by-products adsorbed on the outer layers of the ZnO samples. The EPR spectroscopy coupled with spin-trapping technique showed that the surface of the ZnO samples generates reactive oxygen species (ROS) like hydroxyl (•OH) and singlet oxygen (1O2) as well as carbon-centered radicals. The ZnO materials exhibited a wide spectrum of antimicrobial activity, being active against Gram positive, Gram negative and fungi strains, both in planktonic and, more important, adherent growth state. The decrease of antimicrobial efficiency in the presence of a ROS-scavenger (mannitol) and the decrease of the cell viability with ROS level, suggests that one of the mechanism that governs both the antimicrobial and cytotoxic activity on human liver cells is ROS mediated. However, at active antimicrobial concentrations, the biocompatibility of the tested materials is very good.
Instrument
FP-8300
Keywords
Fluorescence, Photoluminescence, Materials, Optical properties